Stream creation with limited topology information

ABSTRACT

The discovery of a topology of a network with an unknown topology can enable the selection of a data path within the network, and the establishment of a data stream over the selected data path. Routing tables mapping originating nodes to input ports can be created based on the receipt of discovery messages generated by the originating nodes. A source node can select a data path between the source node and a sink node in order to establish a data stream using the routing tables. Data paths can be selected based on, for instance, routing table bandwidth information, latency information, and/or distance information. Data streams can be established over the selected data path, and each node can release any reserved output bandwidth determined to be unnecessary for the data stream.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/597,188, filed Jan. 14, 2015, now U.S. Pat. No. 9,590,825, whichapplication claims priority to, and the benefit of, U.S. ProvisionalApplication No. 61/991,126, filed on May 9, 2014, the contents of whichare hereby incorporated in their entirety.

FIELD

Embodiments of the invention generally relate to the field of networksand, more particularly, to the establishment of a data stream within anetwork of an unknown topology.

BACKGROUND

The transmission of data (such as media data) from a source device to asink device requires the establishment of a data stream between thesource device and the sink device, and possibly through one or moreintermediary devices. In a network with known, established, or statictopologies, the characteristics of each node within the network can beanalyzed, and the data path through which the data stream is establishedcan be selected based on this analysis. However, in networks with anunknown or variable topology, the composition of the network (such asthe number of nodes, the characteristics of each node, theinterconnections between the nodes, and the like) is unknown to anysingle node or is subject to change, limiting the ability to identifythe optimal data path from a source device to a sink device. Inaddition, different types of data streams are associated with differentpriorities. For example, for data streams associated with video games,stream latency is prioritized over stream bandwidth, while for highdefinition video, stream bandwidth is prioritized over stream latency.Accordingly, selecting an optimal data path and establishing acorresponding data stream in a network with unknown topology requiresthe discovery of the network composition and an analysis of thenetworking composition and characteristics of network nodes in view ofdata stream priorities.

SUMMARY

As described herein, the discovery of a topology of a network with anunknown topology can enable the selection of a data path within thenetwork, and the establishment of a data stream over the selected datapath. To discover a network's topology, one or more nodes (“originatingnodes”) within the network can transmit discovery messages on each nodeoutput port coupled to another node identifying the originating node.Nodes within the network, upon receiving the discovery messages, andre-transmit the discovery messages to other nodes. The process isrepeated until each message has traveled each or most data paths withinthe network. Upon receiving a discovery message, a receiving node canadd or update an entry within a routing table corresponding to theoriginating node and the port through which the discovery message wasreceived. The routing table entry can further include bandwidthinformation describing a minimum bandwidth between the originating nodeand the receiving node, latency information describing a total latencybetween the originating node and the receiving node, and distanceinformation describing a distance between the originating node and thereceiving node.

A source node can select a data path between the source node and a sinknode in order to establish a data stream. The source node can query arouting table of the source node with the identity of the sink node toidentify an output port of the source node corresponding to a data pathassociated with the sink node. The intermediary node communicativelycoupled to the source node via the output port in turn queries a routingtable of the intermediary node to identify an output port of theintermediary node corresponding to a data path associated with the sinknode. The process continues until a data path between the source nodeand the sink node is selected. Output ports can be selected based on anysuitable criteria, for instance routing table bandwidth information,routing table latency information, routing table distance information,and the like. In addition, bandwidth estimated to be necessary toestablish the data stream can be reserved by each node within the datapath.

In response to a request to establish a data stream via a selected datapath, a sink node can provide a list of formats compatible with the sinknode to the intermediary node upstream from the sink node within thedata path. The intermediary node can remove formats that are notcompatible with the intermediary node, and can add formats that theintermediary node can transcode into one or more formats within the listof formats. The process continues for each intermediary node in the datapath until the source node receives the updated list of formats. Thesource node subsequently selects a format from the updated list offormats, and provides an indication of the selected format to the datapath node downstream from the source node. The downstream node eitherprovides the indication of the selected format to the next downstreamnode in the data path, or provides an indication of a format that thedownstream node can transcode the selected format into. The processcontinues until the sink node is reached. The source node cansubsequently output data in the selected format, and each node in thedata path can either forward the data to the next node in the data path,or can transcode the data into a different format, and forward thetranscoded data to the next node in the data path. Each node can releaseany unnecessary reserved bandwidth in response to the selection of anoutput format, thus allowing the released bandwidth to be allocated todifferent data streams.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example, and notby way of limitation, in the figures of the accompanying drawings inwhich like reference numerals refer to similar elements:

FIG. 1 is a block diagram illustrating a network topology, according toone embodiment.

FIG. 2 is a block diagram illustrating a network node, according to oneembodiment.

FIG. 3 is a block diagram illustrating a topology discovery process of anetwork, according to one embodiment.

FIG. 4 illustrates a routing table for use by a topology discoveryprocess, according to one embodiment.

FIG. 5 is a flow chart illustrating a process of topology discovery,according to one embodiment.

FIG. 6 is a block diagram illustrating a plurality of data paths withina network, according to one embodiment.

FIG. 7 illustrates a forwarding table for use by a node in establishinga data stream within a network, according to one embodiment.

FIG. 8 is a flow chart illustrating a process for selecting a data pathand establishing a data stream within a network, according to oneembodiment.

FIG. 9 is a block diagram illustrating the establishment of a datastream within a network, according to one embodiment.

FIG. 10 is a flow chart illustrating a process for establishing a datastream within a selected data path, according to one embodiment.

DETAILED DESCRIPTION

As used herein, “network” or “communication network” mean a set ofinterconnected nodes. As used herein, “node” refers to a computingdevice configured to transmit or receive data from one or more othernodes within the network. Examples of nodes include computers (such asspecially configured desktop computers, laptop computers, tablecomputers, and the like), servers (such as specially configured webservers, internet media streaming services, databases, etc.), mobiledevices (such as special configured mobile phones, and the like), mediadevices (such as specially configured media servers, televisions andother displays, speakers, theater equipment, cable boxes, tuner devices,video game consoles, DVD- and Blu-Ray players, and the like), storagedevices (such as specially configured hard drives, cloud storagedevices, video and audio storage devices, and the like), or any othersuitable computing device specially configured to communicate with othernetwork nodes to establish data streams and receive/transmit data asdescribed herein. The data can include digital media content (includingmusic data, audio/video data, gaming data, digital images, and thelike), but can also include any other suitable type of data, includingbut not limited to text data, social networking system data, mobilephone or device data, communications data, spreadsheet data, and thelike. The nodes within the network can transmit and receive data usingany suitable technology, such as Serial ATA (“SATA”), Frame InformationStructure (“FIS”), High-Definition Multimedia Interface (“HDMI”), MobileHigh-Definition Link (“MHL”), Category-5 or Category-6 cable, co-axialcable, or any other suitable networking technology. In addition to wiredconnections between nodes, nodes within a network can be wireless,utilizing technologies such as Wi-Fi, Wi-Max, Bluetooth, LTE, and thelike. A network can include a personal entertainment network, such as anetwork in a household, a network in a business setting, or any othernetwork of devices and/or components. Examples of networks include aLocal Area Network (LAN), Wide Area Network (WAN), Metropolitan AreaNetwork (MAN), intranet, the Internet, etc.

In a network, certain nodes may be a source of data, such as a digitaltelevision tuner, cable set-top box, a mobile device (such as a smartphone), video storage server, and the like. Such nodes are referred toherein as “source nodes”. Other nodes may receive, display, use, orstore media content, such as a digital television, home theater system,audio system, gaming system, video and audio storage server, and thelike. Such nodes are referred to herein as “sink nodes”. As used herein,“data stream” refers to the transmission of data by a source node andthe subsequent receipt of data by a corresponding sink node, throughzero, one, or more intermediary nodes within a data path. As usedherein, “data path” refers to an ordered set of nodes and associatednode connections through which data corresponding to a data stream istransmitted and/or received. In some embodiments, a data path includes asource node and a sink node. In other embodiments, a data path includesa source node, a sink node, and one or more intermediary nodes. Forexample, a data path can include the ordered set {source node, node A,node B, sink node}, through which data is transmitted by the sourcenode, received and re-transmitted at node A, received and re-transmittedby node B, and received at the sink node.

As used herein, a “network with an unknown topology” refers to a networkof nodes such that at least one node does not know or have immediateaccess to the number of nodes in the network, the connections betweenthe nodes in the network, the capabilities or limitations of one or morenodes in a network, or any combination thereof. For example, certainnodes may operate under bandwidth or latency limitations, may not beable to support certain data formats or stream formats, may not be ableto support certain media limitations (such as resolution or media formatlimitations), and the like. Accordingly, source nodes in networks withunknown topologies are often unable to select an optimal data path basedon data stream priorities. For example, in a network with many potentialdata paths from a source node to a sink node, a first data path may beassociated with the greatest bandwidth, a second data path may beassociated with the lowest latency, and a third data path may beassociated with the shortest distance (number of intermediary nodes, or“hops”). Without knowing such a network's topology, a source node may beunable to identify the optimal data path in view of potential datastream priorities, such as maximizing bandwidth, minimizing latency, andminimizing distance. Further, when a network topology changes (forinstance, when a new node is added to a network or an existing node isremoved from the network), the potential data paths in the network canchange, and the optimal data paths in view of data stream prioritieswithin the network may change. Without further analysis of the changednetwork topology, a source node may be unable to identify an optimaldata path within the network.

FIG. 1 is a block diagram illustrating a network topology, according toone embodiment. In the network 100 of FIG. 1, seven nodes (Nodes Athrough G) are communicatively coupled. Node A is communicativelycoupled to Node B. Node B is additionally communicatively coupled toNodes C, D, and F. Node C is additionally communicatively coupled toNode D. Node D is additionally communicatively coupled to Node E. Node Eis additionally communicatively coupled to Node G. Node F isadditionally communicatively coupled to Node G. It should be noted thatfor purposes of the description herein, the network topology illustratedin FIG. 1 is unknown to one or more nodes within the network 100.Further, each node in FIG. 1 can be the same type or configuration ofcomputing device, or can be a different type or configuration ofcomputing device than one or more other nodes. Finally, the type of eachnode connection within the network 100 can be the same, or can bedifferent from one or more other node connections.

Routing Table Creation

FIG. 2 is a block diagram illustrating a network node, according to oneembodiment. In the embodiment of FIG. 2, the node 200 includes aninput/output (“I/O”) engine 202, a port manager 204, a controller 206, abandwidth manager 208, a transcoding engine 210, a display 212, arouting table 214, a forwarding table 216, and a node parameters storage218. It should be noted that in other embodiments, a node 200 caninclude different or additional components than those illustrated herein(such as a data store configured to store received data or speakersconfigured for playback of audio data).

The I/O engine 202 is configured to receive data from and to providedata to other nodes. In other words, the I/O engine 202 provides acommunicative interface between the node 200 and the remainder of thenetwork. The node 200 includes one or more communicative ports, each ofwhich can be communicatively coupled to other nodes. The port manager204 can identify which ports are communicatively coupled to other nodes.For example, if a node has five communicative ports, two of which arecoupled to different nodes, the port manager 204 can identify the twonodes, and in some embodiments can identify the node to which the portsare coupled. The bandwidth manager 208 can reserve bandwidth requestedor required for particular data streams, and can subsequently releaseextra reserved bandwidth not needed for a particular data stream. Thetranscoding engine 210 is configured to transcode data in a first formatinto data of a second format, as described in greater detail below. Thedisplay 212 is configured to display data received by the node 200, forinstance media data.

The controller 206 can discover the topology of a network, can generateor update a routing table 214, can establish a data stream within thenetwork (or can assist a source node in the establishment of a datastream), can generate or update a forwarding table 216, and can optimizean established data stream within the network by releasing unnecessaryreserved bandwidth. In a discovery configuration, the controller 206sends a discovery message to each node connected to the node 208. Tosend a discovery message, the controller 206 queries the port manager204 to identify node ports communicatively coupled to other nodes, andoutputs the discovery message on the identified node ports via the I/Oengine 202. As used herein, “discovery configuration” or “discoverymode” refers to the propagation of discovery messages throughout anetwork in order to identify, characterize, or map one or more aspectsof the network topology.

The discovery messages sent by the controller 206 identify the node 200and can identify the available bandwidth between the node 200 and eachrecipient node. Further, the controller 206 can timestamp the discoverymessage with the current time such that the recipient node can determinethe latency between the node 200 and the recipient node (for instance,by comparing the timestamp to the time the discovery message wasreceived). It should be noted that in some embodiments, latency can bemeasured in other ways, for instance by measuring the amount of timebetween when a node receives a message or other data and then forwardsor acts upon the received data.

In the discovery mode, the controller 206, in response to receiving adiscovery message from a transmitting node (for instance, via the I/Oengine 202), is configured to re-transmit the discovery message to eachadditional node to which the node 200 is connected, for instance byquerying the port manager 204 to identify ports communicatively coupledto nodes other than the port through which the discovery message wasreceived. Before re-transmitting the discovery message to additionalnodes, the controller 206 can determine the available bandwidth betweenthe node 200 and each additional node. If, for a particular additionalnode, the bandwidth between the node 200 and the additional node isdetermined to be less than the bandwidth identified in the discoverymessage, the controller 206 can update the discovery message beforetransmitting the message to the additional node to identify thedetermined bandwidth between the node 200 and the additional node.Accordingly, each node in a data path can identify the lowest bandwidthbetween two adjacent nodes within the data path based on the identifiedavailable bandwidth within the discovery message (referred to herein as“bandwidth information”). It should be noted that in some embodiments,bandwidth is measured bi-directionally, by determining the totalbandwidth available for communication in each direction between twoadjacent nodes.

The controller 206, in response to receiving a discovery message from atransmitting node, can determine the latency between the transmittingnode and the node 200. The controller 206, in response to determiningthe latency, can update the discovery message before re-transmitting thediscover message to include the determined latency. In embodiments inwhich the transmitting node is the originating node (the node that firsttransmitted the discovery message), the controller 206 can include thedetermined latency within the discovery message. In embodiments in whichthe transmitting node is re-transmitting the discovery message from adifferent node, the discovery message can include a latency measure—insuch embodiments, the controller 206 can add the determined latency tothe latency identified within the discovery message to reflect a totallatency between the originating node and the node 200. Accordingly, foreach node in a data path, the node can determine the total latency fromthe originating node through any intermediary nodes within the data pathto the node itself based on the latency identified within the discoverymessage and the determined latency between the node and the transmittingnode from which the discovery message was received (referred to hereinas “latency information”).

In some embodiments, the controller 206 updates the discovery message toreflect the receipt of the discovery message by the node 200, forinstance by incrementing a hops or distance count stored within thediscovery message. For example, after the first re-transmission of adiscovery message, the hops or distance count stored within thediscovery message can be updated to “2”, after the secondre-transmission, the hops or distance count can be updated to “3”, andso forth. Thus, for each node in a data path, the node can determine thetotal distance from the originating node to the node, based on the hopsor distance count stored within the discovery message (referred toherein as “distance information”).

The controller 206 is further configured to update a routing table 214in response to and based on received discovery messages. The controller206 can parse the identity of the originating node from the discoverymessage, and can map the identity of the originating node to the port ofthe node 200 through which the discovery message was received. Further,the controller 206 can parse from the discovery message: a hops ordistance count from the discovery message, a minimum bandwidth withinthe discovery message data path, a total latency between the originatingnode and the node 200, or any combination thereof. Such parsedinformation can be stored within the routing table 214 in conjunctionwith the identity of the originating node and the port mapped thereto.

If a discovery message is received from a particular originating node ona particular port, and if the routing table 214 does not include anentry for the particular originating node and port, the controller 206can create an entry mapping the originating node to the port andincluding addition information, such as a distance from the originatingnode to the node 200, the total latency from the originating node to thenode 200, and the minimum bandwidth between adjacent nodes within thedata path from the originating node to the node 200 via the particularport.

If a discovery message is received from a particular originating node ona particular port, and if the routing table 214 does include an entryfor the particular originating node and port, the controller 206 candetermine whether to replace the entry with information parsed from thereceived discovery message or maintain the entry based on a comparisonof the information within the entry and corresponding information parsedfrom the received discovery message. In some embodiments, the controller206 replaces the routing table entry with information parsed from thereceived discovery message in response to a determination that theinformation parsed from the received discovery message is preferred orsuperior to the information stored in the existing routing table entry.For example, if the minimum bandwidth between adjacent data path nodesidentified in the received discovery message is greater than the minimumbandwidth information stored in the corresponding routing table entry,the controller 206 can replace the routing table entry with informationparsed from the discovery message. Likewise, if the total latencyidentified in the received discovery message is less than the latencyinformation stored in the corresponding routing table entry, thecontroller 206 can replace the routing table entry with informationparsed from the discovery message. In yet another example, if thedistance identified in the received discovery message is less than thedistance information stored in the corresponding routing table entry,the controller 206 can replace the routing table entry with informationparsed from the discovery message. In some embodiments, the controller206 decides to replace the routing table entry with information parsedfrom the discovery message in response to a combination of discoverymessage bandwidth information, latency information, and distanceinformation being preferable to routing table entry bandwidthinformation, latency information, and distance information.

In some embodiments, each node in a network of nodes outputs discoverymessages corresponding to the node, and propagates/re-transmitsdiscovery messages received from other nodes. In such instances, eachnode in a network receives discovery messages originating from eachother node in the network on each port of the node, and discoverymessages traverse each data path from an originating node to each nodein the network. Accordingly, each node in the network is able toidentify an adjacent node within a data path from each port of the nodeto each originating node associated with optimal bandwidth information,latency information, and distance information. In some embodiments,discovery messages are propagated through the network of nodes for athreshold amount of time, until a data path from an originating node toanother node associated with threshold bandwidth, latency, or distanceinformation is identified, for a threshold number of discovery messagere-transmissions by one or more nodes, or based on any other suitablefactor. After a discovery mode, each node in the network stores acorresponding routing table identifying bandwidth, latency, and distanceinformation as described herein for each combination of node port andoriginating node. As described in greater detail below, the routingtables stored by each node can be used to establish data streams withinthe network.

The operation of nodes in a discovery mode as described herein can beinitiated in response to a request from one or more nodes within thenetwork. Further, the discovery mode can be initiated in response to thepassage of a threshold amount of time. The discovery mode can also beinitiated in response to the addition or removal of one or more nodesto/from the network. In such instances, the optimal data paths for oneor more nodes can change in response to the addition or removal of theone or more nodes to/from the network. For example, if an optimal datapath from a first node to a second node traversed a third node, and thethird node was removed from the network, an updated optimal data pathfrom the first node to a second node can be identified based on anupdated set of routing tables stored by the nodes in response to thediscovery mode initiated by the removal of the third node. In discoverymode embodiments initiated in response to the addition or removal of anode from a network, a node can increment a discovery mode counterincluded within the discovery message, allowing nodes that receivediscovery messages to determine that a new discovery mode has beeninitiated and to disregard discovery messages that include countervalues associated with previous discovery modes.

FIG. 3 is a block diagram illustrating a topology discovery process of anetwork 300, according to one embodiment. In the embodiment of FIG. 3,node A generates and outputs a discovery message 302 to node B (the onlynode communicatively coupled to node A) in a first step. Node B parsesthe identity of the originating node (node A) from the discovery messageand creates a routing table entry within the routing table stored atnode B mapping the originating node to the port of node B through whichthe discovery message was received. Node B can additionally parse ordetermine the available bandwidth, the latency, and the distance betweennode A and node B based on the received discovery message 302, and canstore this information in the created routing table entry.

In a second step, node B updates the discovery message as describedabove (for instance, to update the distance information, bandwidthinformation, and latency information associated with the discoverymessage) and re-transmits the discovery message to each node coupled tonode B other than node A. In the embodiment of FIG. 3, node B transmitsthe updated discovery message 304 a to node C, the update discoverymessage 304 b to node D, and the update discovery message 304 c to nodeF. Similar to node B, nodes C, D, and F create routing table entriesbased on the updated discovery messages 304 a, 304 b, and 304 c,respectively.

In a third step, nodes C, D, and F update the discovery messages 304 a,304 b, and 304 c, respectively, and re-transmit the discovery messagesto each node coupled to nodes C, D, and F other than the nodes fromwhich the discovery message was received. In the embodiment of FIG. 3,node C transmits the discovery message 306 a to node D, node D transmitsthe discovery message 306 b to node C and the discovery message 306 c tonode E, and node F transmits the discovery message 306 d to node G. Eachof nodes C, D, E, and G create routing table entries corresponding tothe received discovery messages as described above.

In a fourth step, nodes D, C, E, and G update the discovery messages 306a, 306 b, 306 c, and 306 d, respectively, and re-transmit the discoverymessages to each node coupled to nodes D, C, E, and G other than thenodes from which the discovery message was received. In the embodimentof FIG. 3, node D transmits the discovery message 308 a to node B andthe discovery message 308 b to node E, node C transmits the discoverymessage 308 c to node B, node E transmits the discovery message 308 d tonode G, and node G transmits the discover message 308 e to node E. Eachof nodes B, E, and G create routing table entries corresponding to thereceived discovery messages as described above.

In subsequent steps, the nodes in the network 300 continue to update andre-transmit discovery messages as described above. In these subsequentsteps, each node creates a routing table entry corresponding to theoriginating node A and the port on which a discovery message is receivedif a routing table entry corresponding to the originating node A andport doesn't already exist. If such an entry does exist, each nodeupdates the entry corresponding to the originating node A and port inresponse to a determination that a received discovery information isassociated with one or more of bandwidth information, latencyinformation, or distance information preferable to the bandwidthinformation, latency information, or distance information associatedwith the existing routing table entry. This process is continued untileach node has received a discovery message originating with node A oneach port associated with the node and through each possible data pathbetween the node and the originating node A. Further, it should be notedthat while the embodiment of FIG. 3 is described from the context ofnode A as the originating node, in practice, each node will act as anoriginating node, propagating discovery messages through the network 300until each node stores a completed routing table with entriescorresponding to each originating node and each node port.

FIG. 4 illustrates a routing table for use by a topology discoveryprocess, according to one embodiment. The routing table 400 correspondsto a routing table for node G in the network 300 of FIG. 3. Node Gin thenetwork 300 includes two ports: port 1, which couples node G to node Fin the network 300, and port 2, which couples node G to node E in thenetwork 300. The routing table 400 includes an entry for eachoriginating node within the network 300 (in other words, every nodeother than node G within the network) mapped to each port of node G.Each entry further includes 1) a distance from the originating nodecorresponding to the entry to node G via the port of node Gcorresponding to the entry, 2) the total latency between the originationnode corresponding to the entry and node G via the port of node Gcorresponding to the entry, and 3) the minimum available bandwidthbetween adjacent nodes in the data path from the originating nodecorresponding to the entry and node G via the port of node Gcorresponding to the entry.

For instance, because node G has two ports, the routing table 400 hastwo entries, one for each port, corresponding to each originating node.For example, the routing table entry for node C and port 2 of node Gidentifies 3 hops between node C and node G via port 2, identifies atotal latency of 26 ms between node C and node G via port 2, andidentifies a minimum available bandwidth of 4.1 mb/s between nodeswithin the data path from node C to node G via port 2. The minimum 4.1mb/s bandwidth can represent a bandwidth between node C and node D,between node D and node E, or between node E and node G (the entirety ofthe data path from node C to node G via port 2 of node G). It should benoted that in other embodiments, routing tables can include different oradditional information, such as an identity or type of nodes within aparticular data path, an available bandwidth between each pair ofadjacent nodes in a data path, a latency through each node in a datapath, or any other suitable information. It should be noted thatalthough bandwidths described herein are between 2.0 mb/s and 10.0 mb/s,in practice, any possible bandwidth, including bandwidths less than 2.0mb/s and greater than 10.0 mb/s (such as 1.0 gb/s and greater) can beutilized within a network and tracked within forwarding tables.

FIG. 5 is a flow chart illustrating a process of topology discovery,according to one embodiment. A node receives 500 a discovery message viaa first node port from a transmitting node. In some embodiments, thetransmitting node is an originating node of the discovery message, whilein other embodiments, the transmitting node is a node within the datapath from an originating node to the node configured to re-transmit thediscovery message.

The identity of the originating node associated with the discoverymessage is parsed 502 from the discovery message. The lowest bandwidthbetween nodes in the data path from the node receiving the discoverymessage to the originating node is identified 504 based on the discoverymessage. The total latency between the node and the originating node isidentified 506 based on the discovery message. The total distancebetween the node and the originating node is also identified 508 basedon the discovery message.

An entry associated with the originating node and the first node port ina routing table corresponding to the node is queried 510. In someembodiments, the routing table does not include an entry associated withthe originating node and the first node port—in such embodiments, anentry is created based on the identity of the originating node, thefirst node port, the identified lower bandwidth, the identified totallatency, and the identified total distance. In the event that therouting table includes an entry corresponding to the originating nodeand the first node port, the entry can be replaced 512 with theidentified lowest bandwidth, the identified latency, and the identifiedtotal distance if the corresponding information included within therouting table entry is determined to be inferior to the identifiedbandwidth, latency, and distance. For instance, the entry can bereplaced if the stored total latency is greater in magnitude than theidentified total latency.

Data Path Selection, Establishing Data Streams, and Forwarding TableCreation

FIG. 6 is a block diagram illustrating a plurality of data paths withina network 600, according to one embodiment. In the network 600, a firstdata path from a source node A to a sink node D is defined bycommunicative link 602 a from node A to node B and communicative link604 a from node B to node D. A second data path from a source node G toa sink node A is defined by communicative link 602 b from node G to nodeF, communicative link 604 b from node F to node B, and communicativelink 606 b from node B to node A. A third path from a source node C to asink node E is defined by communicative link 602 c from node C to nodeB, communicative link 604 c from node B to node D, and communicativelink 606 c from node D to node E. It should be noted that, asillustrated in FIG. 6, nodes can accommodate different data streams overcommon communicative links, as will be discussed below in greaterdetail.

A data path from a source node to a sink node can be selected, forinstance to establish a data stream between the sink node and the sourcenode, using the routing tables associated with each node in a network(such as the network 600) by identifying, for each node, an output portcorresponding to the sink node (or the “originating node” of FIG. 4).The data path is selected one node at a time by querying the routingtable associated with a first node (such as the source node) to selectan output node port corresponding to a second node in the data path,querying a routing table associated with the second node to select anoutput node port corresponding to a third node in the data path, and soon until a routing table associated with the n^(th) node is queried andan output node port corresponding to the sink node is selected. In otherwords, the data path is selected one node at a time, starting with thesource node, selecting a next node in the data path by selecting anoutput node port, and continuing until the sink node is reached. Duringthe selection of a data path, upon reaching the sink node in the datapath, the sink node can send a confirmation message to the source.

In selecting a data path through a network, the output node port foreach node in a data path can be selected using the routing tableassociated with each node based on 1) the identity of the sink node, and2) based on any additional suitable criteria. In some embodiments, anoutput node port can be selected based on a type of data stream, basedon an identity or type of a source node in the data path, based on anidentity or type of a sink node in a data path, based on a type of databeing transmitted, or based on any other suitable criteria. For example,for video data, the routing table associated with each node in the datapath can be queried to identify the output node port corresponding tothe desired sink node and associated with the highest minimum bandwidth.Similarly, for video game console source nodes, the routing tableassociated with each node in the data path can be queried to identifythe output node port corresponding to the desired sink node andassociated with the lowest total latency. In some embodiments, an outputnode port can be selected based on one or more data stream criteria orpriorities. For instance, if a data stream priority is the selection ofa data path corresponding to the greatest minimum bandwidth, thesmallest latency, or the shortest distance between the source node andthe sink node, routing tables associated with each node can be queriedto select an output node port accordingly.

Data paths can be selected within networks in order to establish a datastream over the data path. Accordingly, a data path can be selected inresponse to a request to establish a data stream. Data streams can beidentified within a network 600 by a global stream identifier (or“global ID”). Global IDs are globally unique, allowing each node withina network to uniquely identify a data stream using the global ID. GlobalIDs are semi-permanent fixtures, enabling nodes to track and rememberstream IDs over events such as power losses and re-routings of datapaths due to, for example, node shutdowns. Further, each node within anetwork can be included in more than one data path, and can output datacorresponding to more than one data stream on a single output node port.In addition to global IDs, different data streams outputted on a singleoutput node port can be identified or differentiated between by a localstream identifier (or “local ID”). Local IDs enable are unique to aparticular node, enabling a node to differentiate between data streamswithin the node. Accordingly, local IDs can be small in size, enabling anode to efficiently filter between and forward data streams. Each datastream can be associated with a required bandwidth, and each node in adata stream's data path can reserve the required bandwidth (or anestimate of the required bandwidth if the required bandwidth is unknown)between the node and a next node in the data path, for instance using abandwidth manager (such as the bandwidth manager 208). The bandwidthmanager 208 can reserve the output bandwidth required by a data streamon an output node port, preventing other data streams from using thebandwidth. It should be noted that although the selection of a data pathand the establishment of a data path are described separately herein, insome embodiments, a data path can be selected concurrently oroverlapping in time with the establishment of a data stream.

To establish a data stream over the selected data path, each node in thedata path receives a data stream creation request and forwards therequest to the next node in the data path, and in response to therequest, each node updates a corresponding forwarding table (such as theforwarding table 216) stored at each node to identify the data path anddata stream. To update a forwarding table in response to establishing adata stream, a forwarding table entry corresponding to the data streamis generated. The generated forwarding table entry can include a globalID for the data stream, one or more local IDs for the data stream (forinstance a first local ID for an input port and a second local ID for anoutput port), an input port corresponding to the data path, an outputport corresponding to the data path, an input port bandwidth, and anoutput port bandwidth reserved for the data stream. The global ID andthe required bandwidth for the data stream can be identified within thedata stream request. The local ID can be generated by each node toenable the node to differentiate between multiple data streamscorresponding to the same output node. The input port can be determinedbased on the port upon which the data stream creation request isreceived. The output port can be identified by data stream creationrequest, by reference to the data path, or by querying the routing tablewith the input port and the source node, and using the output nodeselection criteria used to select the data path.

Accordingly, a forwarding table entry corresponding to a data stream iscreated in a forwarding table for each node in the data path from thesource node to the sink node. When a forwarding table entrycorresponding to the sink node is created, the sink node can output acompletion signal indicating that the data stream has been established,which is forwarded to the source node, indicating that the source nodecan begin outputting data to the sink node within the established datastream. Data corresponding to a data stream received at a node withinthe data path is forwarded by the node to a next node in the data pathby querying the forwarding table to identify an output node for the datastream, and by outputting the received data via the identified outputnode.

FIG. 7 illustrates a forwarding table for use by a node in establishinga data stream within a network, according to one embodiment. Theforwarding table 700 illustrated in FIG. 7 is a forwarding tablegenerated and stored by node B in the network 600 of FIG. 6. Theforwarding table 700 includes entries representative of a data streamfor each selected data path within the network 600. A first data streamrepresented by global ID “A” is established over the data path from nodeA to node B via port 1 (the input port), and from node B to node D viaport 3 (the output port). Node B assigns data stream A the local ID “X”,and reserves 4.4 mb/s of output bandwidth on port 3 for data stream A.Accordingly, the forwarding table entry corresponding to data stream Aincludes the local ID X, the input port 1, the output port 3, and thereserved 4.4 mb/s bandwidth. Similarly, forwarding table entriescorresponding to a second stream represented by global ID “B” and athird stream represented by global ID “C” are created. It should benoted that although only output bandwidth is illustrated in theforwarding table of FIG. 7, in practice forwarding tables can alsoinclude input bandwidth, which is initially set to the maximum bandwidthpossible on the input port, and then is adjusted in response to thereleasing of unnecessary reserved bandwidth in response to establishinga data stream.

FIG. 8 is a flow chart illustrating a process for selecting a data pathand establishing a data stream within a network, according to oneembodiment. In the embodiment of FIG. 8, a request to establish a datastream is received 800 on an input port of a first node. The requestidentifies a sink node, and can identify a required bandwidth for thedata stream. A routing table corresponding to the first node is queriedto select an output port associated with the sink node. In someembodiments, an output port is selected based one or more of bandwidthinformation, latency information, and distance information correspondingto the sink node in the routing table.

Output port bandwidth corresponding to the identified output port isreserved 804, for instance based on the format of the requested datastream. A forwarding table entry is created 806 within a forwardingtable of the first node identifying the data stream, the first inputport, and the selected output port. In some embodiments, the forwardingtable entry further includes a local stream identifier and the reservedbandwidth associated with the selected output port.

Subsequent to the creation of a forwarding table entry corresponding tothe data stream, data associated with the data stream is received 808 onthe input port. In response, the forwarding table is queried 810 toidentify the output port associated with the data stream. In someembodiments, the forwarding table is queried based on a data streamidentifier or a local stream identifier. The received data is thenoutputted 812 on the identified output port. It should be noted that insome embodiments, a data path is first selected, a list of availableformats is propagated from the sink node to the source node, a format ischosen by the source node, and only then is the bandwidth reserved basedon the chosen format.

FIG. 9 is a block diagram illustrating the establishment of a datastream within a network, according to one embodiment. It networks withunknown topologies, data streams can be established incrementally toaccount for the unknown capabilities of each node in a data path. In theembodiment of FIG. 9, a data path is selected between a source node 900and a sink node 906. The selected data path includes nodes 902 and 904.To establish a data stream, the source node 900 can send a data streamrequest (not illustrated) to the sink node 906 through the nodes 902 and904. The data stream request can identify a type of data stream (such asa type or format of data being transmitted via the data stream), arequired or approximate data stream bandwidth, and/or any other suitableinformation associated with the data stream. Each node in the selecteddata path reserves the amount of output bandwidth required or requestedby the data stream request, for instance in response to receiving thedata stream request, in response to receiving a confirmation oracceptance of the requested by the sink node 906, or in response to anyother suitable event.

In response to receiving a request to establish a data stream, the sinknode 906 compiles a list of data formats with which the sink node 906 iscompatible (e.g., a data format that a node is capable of receiving,processing, outputting, storing, and/or displaying). In someembodiments, the list of data formats is curated based on the request toestablish a data stream (for instance, if the request to establish adata stream identifies a video format, the sink node 906 can filter theprovided list of data formats to video formats). The sink node 906provides the list of available formats 910 to the node 904. The node 904curates the list 910 to remove formats that the node 904 is incompatiblewith, producing a first updated list 912. In some embodiments, the node904 can additionally add formats to the first updated list 912, such asformats that the node 904 is capable of transcoding into one or moreformats within the list 910 (using, for example, the transcoding engine210 of the node 200). For example, if the list 910 includes the .AVIvideo format but not the .MP4 video format, and the node 904 is capableof transcoding .MP4 video to .AVI video, the node 904 can add the .MP4format to the list 912. When the data stream is subsequently establishedand the node 904 receives .MP4 format video data, the node 904 can thentranscode the .MP4 video data into .AVI video data, and can output thetranscoded .AVI format video data to the sink node 906.

The node 902, in response to receiving the updated list of formats 912from the node 904, in turn produces a list of formats 914 by removingformats that the node 902 is incompatible with and adding formats thatthe node 902 is capable of transcoding into one or more formats withinthe list 912. The list 914 is received by the source node 900. Thesource node 900 selects a format from the list 914, for instance basedon a pre-determined data format ranking or preference of the source node900 or the sink node 906, based on an amount of bandwidth required byeach format within the list 914, based on an amount of transcodingrequired within the data stream, or based on any other suitable factor.The source node 900 can optimize the data stream by determining theamount of bandwidth required to establish the data stream based on theselected format, and releasing any previously reserved bandwidth notneeded to output data in the selected format (using, for instance, thebandwidth manager 208 of the node 200). For instance, if the source node900 has previously reserved 10 mb/s for the data stream (for instance,in response to output a request to establish a data stream, in responseto receiving a confirmation of receiving the request from the sink node906, in response to the selection of a data path, or in response to anyother suitable factor), but the data format selected by the source node900 only requires 7 mb/s to output, then the source node 900 can free 3mb/s of the reserved 10 mb/s, allowing the source node 900 to allocatethe 3 mb/s bandwidth to other data streams. It should be noted that asused herein, “reserved bandwidth” can refer to either bandwidth reservedfor a particular node output, or bandwidth reserved across all nodeoutputs (total node output bandwidth).

The source node 900 provides the selected format 916 to the node 902.The node 902, in response to receiving the selected format 916,determines if the node 902 is compatible with the selected format 916.In the event that the node 902 is compatible with the selected format916, the node 902 outputs the selected format 918 to the node 904. Inthe event that the node 902 is not compatible with the selected format,the node 902 selects a different format that 1) the node 902 canprocessing and/or output, and 2) into which the node 902 is capable oftranscoding received data in the received format 916. The node 902 thenoutputs the selected format 918 to the node 904 (which will be a formatfrom the list of formats 912). Similar to the source node 900, the node902 releases any unnecessary previously reserved bandwidth forallocation to other data streams based on the selected format 918. Node904 similarly receives the selected format 918, and outputs it as theselected format 920, or selects a different format into which the node904 can transcode the format 918, and outputs the selected differentformat 920. The node 904 can also releases any unnecessary previouslyreserved bandwidth for allocation to other data streams based on theselected format 920.

The sink device 906 receives the selected format 920 (which will be aformat from the list of formats 910), and provides a confirmation to thesource node 900 (via the nodes 902 and 904) to proceed with providingdata from the data stream. The source node 900, in response to receivingthe confirmation from the sink node 906, outputs data in the data format916. The node 902 receives the data, and outputs the data if the format916 and the format 918 are the same format, or transcodes the data intothe format 918 if the formats are different. The node 904 receives thedata from the node 902, and outputs the data if the format 918 and theformat 920 are the same, or transcodes the data into the format 920 ifthe formats are different. The sink node 906 receives the data from thenode 904, and (for example) displays the received data via the display212, stores the data, forwards the data to an additional node not shownin the embodiment of FIG. 9, or processes the data if necessary.

FIG. 10 is a flow chart illustrating a process for establishing a datastream within a selected data path, from a source node to a sink node,according to one embodiment. A sink node provides 1000 a list ofavailable data formats (data formats which the sink node can receiveand/or process) to an intermediary node within the selected data path.Each intermediary node receives the list from a downstream node (thesink node or a node between the intermediary node and the sink node)updates 1002 the list of formats to remove unavailable data formats(formats that an intermediary node is unable to receive and/or process),and to add formats from which an intermediary node can transcode intoone or more formats from the provided list. The updated list is received1004 at the source node in the selected data path. The source nodeselects 1006 a format from the updated list of available formats. Thesource node released 1008 reserved bandwidth based on the selectedformat (for instance, reserved bandwidth not necessary for outputtingdata in the selected format). Each intermediary node receives theselected data format or a format to which data in the selected format istranscoded from an upstream node (the source node or a node between theintermediary node and the source node) and similarly releases 1010reserved bandwidth based on the selected data format or a format towhich data in the selected format is transcoded. The sink node cansubsequently provide a confirmation to the source node to begintransmitting data, and the source node, in response can output data inthe selected data format.

The foregoing description of the embodiments has been presented for thepurpose of illustration; it is not intended to be exhaustive or to limitthe embodiments to the precise forms disclosed. Persons skilled in therelevant art can appreciate that many modifications and variations arepossible in light of the above disclosure.

Some portions of this description describe the embodiments in terms ofalgorithms and symbolic representations of operations on information.These algorithmic descriptions and representations are commonly used bythose skilled in the data processing arts to convey the substance oftheir work effectively to others skilled in the art. These operations,while described functionally, computationally, or logically, areunderstood to be implemented by computer programs or equivalentelectrical circuits, microcode, or the like. Furthermore, it has alsoproven convenient at times, to refer to these arrangements of operationsas modules, without loss of generality. The described operations andtheir associated modules may be embodied in software, firmware,hardware, or any combinations thereof. One of ordinary skill in the artwill understand that the hardware, implementing the described modules,includes at least one processor and a memory, the memory comprisinginstructions to execute the described functionality of the modules.

Any of the steps, operations, or processes described herein may beperformed or implemented with one or more hardware or software modules,alone or in combination with other devices. In one embodiment, asoftware module is implemented with a computer program productcomprising a computer-readable medium containing computer program code,which can be executed by a computer processor for performing any or allof the steps, operations, or processes described.

Embodiments may also relate to an apparatus for performing theoperations herein. This apparatus may be specially constructed for therequired purposes, and/or it may comprise a general-purpose computingdevice selectively activated or reconfigured by a computer programstored in the computer. Such a computer program may be stored in a nontransitory, tangible computer readable storage medium, or any type ofmedia suitable for storing electronic instructions, which may be coupledto a computer system bus. Furthermore, any computing systems referred toin the specification may include a single processor or may bearchitectures employing multiple processor designs for increasedcomputing capability.

Embodiments may also relate to a product that is produced by a computingprocess described herein. Such a product may comprise informationresulting from a computing process, where the information is stored on anon transitory, tangible computer readable storage medium and mayinclude any embodiment of a computer program product or other datacombination described herein.

Finally, the language used in the specification has been principallyselected for readability and instructional purposes, and it may not havebeen selected to delineate or circumscribe the inventive subject matter.It is therefore intended that the scope of the embodiments be limitednot by this detailed description, but rather by any claims that issue onan application based herein. Accordingly, the disclosure of theembodiments is intended to be illustrative, but not limiting.

What is claimed is:
 1. A method comprising: receiving, at anintermediary node comprising electronic circuitry in a data path from afirst node, a request to establish a data stream; outputting, by theintermediary node to a second node, the request to establish the datastream; receiving, by the intermediary node from the second node, a listof formats compatible with the second node; generating an updated listof formats by: removing formats from the received list of formats withwhich the intermediary node is not compatible; and adding one or moreadditional formats to the list, each additional format comprising aformat which the intermediary node can transcode into one or more of theformats within received the list of formats; providing the updated listof formats to the first node; and receiving confirmation of a selectedformat from the first node, the selected format selected by nodeupstream from the intermediary node within the data path based on aninitial format selected by a source node of the data path and comprisinga format from the updated list of formats, the upstream node configuredto transcode data in the initial format to data in the selected format.2. The method of claim 1, wherein the source node receives the updatedlist of formats.
 3. The method of claim 1, wherein the source nodereceives a list of formats generated by a node between the source nodeand the first node based at least in part on the updated list offormats.
 4. The method of claim 1, further comprising: in response tothe selected format comprising a format on the received list of formats,providing the received confirmation of the selected format to the secondnode; and in response to the selected format comprising a format on theupdated list of formats but not the received list of formats: selectingan updated format, the updated format comprising a format into which theintermediary node can transcode the selected format; and providing anupdated confirmation to the second node, the updated confirmationcomprising the updated format.
 5. The method of claim 1, furthercomprising: receiving data stream data from the first node in theselected format; in response to the selected format comprising a formaton the received list of formats, outputting the received data to thesecond node; and in response to the selected format comprising a formaton the updated list of formats but not the received list of formats:transcoding the received data into an updated format, the updated formatcomprising a format on the received list of formats; and providing thetranscoded data to the second node.
 6. A system comprising: anintermediary node comprising electronic circuitry within a data path,the intermediary node configured to communicate with a first node and asecond node in the data path, the intermediary node configured toperform steps comprising: receiving, from the first node, a request toestablish a data stream; outputting, to the second node, the request toestablish the data stream; receiving, from the second node, a list offormats compatible with the second node; generating an updated list offormats by: removing formats from the received list of formats withwhich the intermediary node is not compatible; and adding one or moreadditional formats to the list, each additional format comprising aformat which the intermediary node can transcode into one or more of theformats within received the list of formats; providing the updated listof formats to the first node; and receiving confirmation of a selectedformat from the first node, the selected format selected by nodeupstream from the intermediary node within the data path based on aninitial format selected by a source node of the data path and comprisinga format from the updated list of formats, the upstream node configuredto transcode data in the initial format to data in the selected format.7. The system of claim 6, wherein the source node receives the updatedlist of formats.
 8. The system of claim 6, wherein the source nodereceives a list of formats generated by a node between the source nodeand the first node based at least in part on the updated list offormats.
 9. The system of claim 6, the intermediary node configured toperform further steps comprising: in response to the selected formatcomprising a format on the received list of formats, providing thereceived confirmation of the selected format to the second node; and inresponse to the selected format comprising a format on the updated listof formats but not the received list of formats: selecting an updatedformat, the updated format comprising a format into which theintermediary node can transcode the selected format; and providing anupdated confirmation to the second node, the updated confirmationcomprising the updated format.
 10. The system of claim 6, theintermediary node configured to perform further steps comprising:receiving data stream data from the first node in the selected format;in response to the selected format comprising a format on the receivedlist of formats, outputting the received data to the second node; and inresponse to the selected format comprising a format on the updated listof formats but not the received list of formats: transcoding thereceived data into an updated format, the updated format comprising aformat on the received list of formats; and providing the transcodeddata to the second node.
 11. A non-transitory computer-readable storagemedium storing executable computer instructions configured to, whenexecuted by electronic circuitry of an intermediary node within a datapath, cause the intermediary node to perform steps comprising:receiving, from a first node, a request to establish a data stream;outputting, to a second node, the request to establish the data stream;receiving, from the second node, a list of formats compatible with thesecond node; generating an updated list of formats by: removing formatsfrom the received list of formats with which the intermediary node isnot compatible; and adding one or more additional formats to the list,each additional format comprising a format which the intermediary nodecan transcode into one or more of the formats within received the listof formats; providing the updated list of formats to the first node; andreceiving confirmation of a selected format from the first node, theselected format selected by node upstream from the intermediary nodewithin the data path based on an initial format selected by a sourcenode of the data path and comprising a format from the updated list offormats, the upstream node configured to transcode data in the initialformat to data in the selected format.
 12. The non-transitorycomputer-readable storage medium of claim 11, wherein the source nodereceives the updated list of formats.
 13. The non-transitorycomputer-readable storage medium of claim 11, wherein the source nodereceives a list of formats generated by a node between the source nodeand the first node based at least in part on the updated list offormats.
 14. The non-transitory computer-readable storage medium ofclaim 11, the instructions configured to cause the intermediary node toperform further steps comprising: in response to the selected formatcomprising a format on the received list of formats, providing thereceived confirmation of the selected format to the second node; and inresponse to the selected format comprising a format on the updated listof formats but not the received list of formats: selecting an updatedformat, the updated format comprising a format into which theintermediary node can transcode the selected format; and providing anupdated confirmation to the second node, the updated confirmationcomprising the updated format.